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(1) Field of the Invention
The invention concerns an electrical plug-type connector, in particular a socket or a cigar(ette) lighting device for motor vehicles.
(2) Description of Related Art
One electrical plug-type connector of the aforementioned type, for example that known from German Patent 3932602C1, comprises a sleeve-like guide part for the axially displaceable acceptance of a cigar(ette) lighter or a connection plug of an electrical device. A first contact is arranged in the sleeve base section on an insulation carrier to be acted upon by a counter contact. The electrically-conductive guide part forms a second fixed contact that acts upon other counter contacts. Thermal overload protection is also provided on the known electrical plug-type connector.
A known electrical plug-type device is indeed functional in that it provides thermal protection. However, the known device is disadvantageous to produce, since the PTC resistor must be riveted with other parts, and rapid response to current overload is not guaranteed when the conventional plug-type connector is used as a socket.
The object of the invention is to improve an electrical plug-type connector of the aforementioned type such that it requires only few parts for the thermal protection function, so that it can be assembled in simple fashion with common parts, thereby assuring a high degree of functionality and robustness against inappropriate manipulation of the device, and so that the protection device responds rapidly and positively to a current overload of more than, for example, 15 A.
This objective is satisfied as follows.
An exemplary embodiment of an electrical plug-type connector, in particular a socket or a cigar(ette)-lighting device in motor vehicles, includes a sleeve-like guide part (1). The guide part (1) axially accepts a cigar(ette) lighter or a connector plug of an electrical device. A fixed contact (5) is arranged on an insulation carrier (4) in the base section of the guide part (1). The at least sectionally electrically-conducting guide part (1) forms a second fixed contact that acts upon other counter contacts. Overload protection (6) is also provided.
In accordance with the invention, a sheet metal insert is provided parallel to the overload protector and at a distance from the insulation carrier, and extending inside the base region of the sleeve. An electrically-conductive bimetal-switch spring is fixed to the underside of the sheet metal insert. In the non-operative condition, the bimetal-switch spring acts upon the first fixed contact or upon a side contact (10) connected with the side contact (10). Here, the diameter of the sheet metal insert is less that the internal diameter of the sleeve-like guide part, whereby the sheet metal insert can be introduced axially from the opening side into the guide part. In the final-assembly condition, the sheet metal insert is connected by a snap/catch connector with the insulation carrier spaced such that a pivot-region opening is provided for the bimetal-switch spring in the energized condition.
The invention provides a cohesive functional sub-assembly that can be pre-assembled, and that can also be pre-tested, in particular its electrical and thermal protection properties. The pre-assembled functional subassembly, consisting of sheet metal insert, bimetal-switch spring and possibly a bimetal spring, which locks a cigar(ette) lighter during the heat-up phase and thermally releases after the heat-up phase, can be snapped onto the pre-assembled basic subassembly, consisting of the insulation carrier and the center contact and/or a side contact, with only a single motion. Compared to known devices, an electrical plug device in accordance with the principles of the claimed invention responds more quickly. It is also easy to assemble, requires little space and can be pre-tested for its thermal properties.
In order to further simplify the mutual mounting of the two subassemblies, the insulation carrier is provided on the edge side with position-limiting projections extending axially over the base section. These projections also define the distance of the sheet metal insert from the base section of the insulation carrier. In the final mounting condition, the sheet metal insert, with L-shaped upward bends in the edge thereof, overlaps the position-limiting projections, whereby the two parts may be locked together by snap/catch connector to achieve a stable mechanical hold. The L-legs of the L-shaped upward bends of the edge here lie on the position-limiting projections.
A particularly advantageous snap/catch connector may be used, so as to provide durable four-point attachment of the pre-assembled functional subassembly to the basic subassembly, and to protect the attachment from manipulation.
In such an embodiment, the sheet metal insert (7) may be provided with springy detents (16) that engage into catch openings (17) of the insulation carrier (4). The detents (16) may be arranged in cutouts (15) of the L-shaped edge upward bends (13). In addition, the cutouts (15) of the L-shaped edge upward bends (13) may penetrate through the flat area of the sheet metal insert (7) as well as both L-legs (14).
The bimetal-switch spring is connected in off-center fashion with the underside of the sheet metal insert, whereby a longer switch travel as well as a relatively great bimetal-switch spring length are made possible. The switch travel is further increased by arranging the side contact in a recess of the insulation carrier. Additionally, pre-fixing for the rivet-mounting process is made possible through a recess in the insulation carrier, enabling insertion of the side contact.
Defined anchoring and supporting of the bimetal spring on the insert is enabled by a plate-like bulge of the sheet metal insert in its center area.
The steps for producing and mounting electrical plug-type connector as described herein are as follows.
An at least sectionally electrically conductive sleeve-like guide part, adapted for axially accepting a cigar(ette) lighter or a connector plug of an electrical device, is provided.
An insulation carrier is provided, and a contact support is mounted with a side contact through a central rivet on the base section of the insulation carrier.
The insulation carrier is mounted in the base region of the sleeve-like guide part.
A sheet metal insert is provided, the outer diameter of the sheet metal insert being less than the internal diameter of the sleeve-like guide part.
A bimetal-switch spring is electrically attached to the underside of the sheet metal insert. An approximately U-shaped sheet metal insert is also attached with the U-middle section on the sheet metal insert, in such manner that the U-side sections extend out over the sheet metal insert.
The functional unit forming a thermal overload protector, consisting of the sheet metal insert, bimetal switch spring and bimetal spring, is thermally pre-tested. If required, it may also be calibrated.
The functional unit is inserted into the sleeve part in the plug-in direction.
A snap/catch connector is produced between the sheet metal insert and the insulation carrier in such manner that the bimetal-switch spring acts upon the side contact with one contact element, when in the non-actuated condition.